Our invention relates to apparatus employing disk-like record media for the recording and/or reproduction of data, and more specifically to apparatus for data transfer with flexible magnetic disks now commonly referred to as floppy disks, although we do not wish our invention to be unnecessarily limited to this particular type of record medium.
Floppy disks have found widespread acceptance in information processing and allied industries, as well as in offices in general, as compact data storage media. Being thin and limply flexible, the disks are usually encased in more rigid, apertured envelopes to make up disk assemblies or cartridges that are self supporting. There have also been suggested and used a variety of devices, known as floppy disk drives (FDDs), for data transfer to and from such disk cartridges. Dalziel et al. U.S. Pat. No. 3,678,481 and Castrodale et al. U.S. Pat. No. 4,089,029 represent examples of such known FDDs.
FDDs are usually not self contained; they are subservient to host equipment typically comprising a central processor unit (CPU) and an associated controller. A familiar example of such mode of use is the daisy chaining of two or more FDDs to a CPU via a controller, with the FDDs in parallel relation to each other. Each FDD intended for use with host equipment has no power switch of its own. In a data transfer system comprising a CPU, a controller, and FDDs, for example, only one power switch serves the complete system. A problem has arisen in conjunction with this standardized power supply system. The FDDs are not necessarily used for data transfer at all times after the power switch of the complete system is turned on. Conventionally, however, power has been fed to the various components of the FDDs even when they are not in actual use. This of course has incurred a substantial waste of energy.